Chapter 12 Vocabulary: Cell Cycle

anaphase

chromosomes separate and move to opposite ends of the cell

aster

a radial array of short microtubules that extends from each centrosome toward the plasma membrane

binary fission

a form of asexual reproduction in single-celled organisms by which one cell divides into two identical daughter cells, each with a complete set of genetic material

cell cycle

series of events in which a cell grows, prepares for division, and divides to form two daughter cells

cell cycle control system

the regulatory mechanism that oversees the orderly progression of a cell through its various stages of growth, division, and replication, manages the key checkpoints and phases of the cell cycle, ensuring that each phase is completed accurately before the cell proceeds to the next stage

cell plate

a double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis, made of vesicles with cellulose and polysaccharides

centromere

the region of the chromosome that holds the two sister chromatids together

centrosome

a structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division, a centrosome has two centrioles

checkpoint

a control mechanism or regulatory point during the cell cycle where the cell evaluates internal and external conditions before proceeding to the next stage of the cycle

chromatin

the material of which the chromosomes of organisms other than bacteria are composed, consists of protein, RNA, and DNA

chromosome

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

cleavage furrow

the first sign of cytokinesis during cell division in an animal cell; a shallow groove in the cell surface near the old metaphase plate

cyclin

one of a family of closely related proteins that regulate the cell cycle in eukaryotic cells

cyclin-dependent kinases (CDK)

enzymes found in eukaryotic cells that play a pivotal role in regulating the progression of the cell cycle, work in conjunction with cyclin proteins to control various stages of the cell cycle by adding phosphate groups to other proteins, a process known as phosphorylation

cytokinesis

cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells

G0 phase

often referred to as the "resting phase," is a stage in the cell cycle where cells temporarily exit from the active cell division cycle, cells in the G0 phase are in a non-dividing, quiescent state, either temporarily or indefinitely

G1 phase

also called gap 1 phase, the cell grows physically larger, copies organelles, and makes the molecular building blocks it will need in later steps, cell also synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis

G2 phase

also called gap 2 phase, serves as a checkpoint in the cell cycle, ensuring that DNA replication is complete and accurate and that the cellular environment is suitable for cell division (similar to G1 phase)

benign

harmless, not cancerous

gamete

a mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

interphase

the preparatory/resting phase preceding cell division and consists of three main stages: G1 (Gap 1), S (Synthesis), and G2 (Gap 2).

kinetochore

a protein structure that forms on the centromere of a chromosome during cell division, serves as an attachment site for spindle fibers (microtubules) that aid in the movement and segregation of chromosomes

M phase

M phase, or Mitotic phase, is a stage of the cell cycle during which cell division occurs, is divided into two main processes: mitosis and cytokinesis. crucial for the growth, repair, and reproduction of cells. It ensures that genetic material is accurately distributed between the daughter cells, allowing for the propagation and maintenance of genetic information

malignant

harmful, cancerous

meiosis

a type of cell division that occurs in sexually reproducing organisms to produce gametes (such as sperm and eggs) with half the number of chromosomes found in normal body cells, it involves two successive divisions, resulting in the formation of four daughter cells, each containing half the number of chromosomes of the original cell

metaphase

where chromosomes align themselves along the center of the cell called the metaphase plate, during this phase, the chromosomes, which have already replicated, become condensed and are attached to spindle fibers that extend from opposite ends of the cell

metastasis

the spread of cancer cells from the original (primary) tumor to other parts of the body, where they establish secondary tumors

mitosis

a single cell divides into two identical daughter cells, consists of a series of stages—prophase, metaphase, anaphase, and telophase—during which the cell's chromosomes condense, align in the center, separate, and are eventually enclosed in separate nuclei within the newly formed daughter cells that each have the same number and kind of chromosomes as the parent nucleus

mitotic spindle

structure composed of microtubules that forms during cell division (mitosis and meiosis) and plays a critical role in the movement and segregation of chromosomes. It is responsible for organizing and separating the duplicated chromosomes into two identical sets, ensuring that each daughter cell receives the correct number of chromosomes

origin of replication

site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides

prometaphase

stage of eukaryotic cell division that falls between prophase and metaphase, the cell's chromosomes have condensed and the cell's centrosome, or microtubule organizing center, has divided and moved to opposite sides of the cell

prophase

initial stage of mitosis and of the mitotic division of meiosis. During prophase, the chromosomes condense and become visible, consisting of two chromatids, the nucleolus and nuclear membrane disappear, and the mitotic spindle is formed

S phase

phase of the cell cycle in which DNA is replicated, occurring between the G1 phase and G2 phase

sister chromatids

two identical copies of a chromosome that are formed by DNA replication during the S phase of the cell cycle and are joined by a centromere

somatic cell

refers to any cell in the body of a multicellular organism that is not involved in the production of gametes, basically any cell in the body that is not sperm or an egg

telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed